Reinforcement insert for tissue graft

ABSTRACT

Devices and methods for reinforcing tissue grafts are described herein. In one embodiment, an implant is described that includes a proximal end portion having a through-hole formed therein, a distal end portion, and a reinforcing insert disposed in the through-hole. The insert includes a proximal face, a distal face opposed to the proximal face, a first upper surface extending between the proximal and distal faces and having a generally convex shape that abuts against at least a portion of a sidewall of the through-hole, and a second lower surface extending between the proximal and distal faces and having a generally concave shape. The second lower surface and portions of the sidewall of the through-hole not abutted by the first upper surface form a reinforced through-hole of the implant.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of and claims priority to U.S.patent application Ser. No. 16/688,806, filed Nov. 19, 2019, andentitled “Reinforcement Insert for Tissue Graft,” which is a divisionalof and claims priority to U.S. patent application Ser. No. 14/494,346,filed Sep. 23, 2014, and entitled “Reinforcement Insert for TissueGraft,” and now issued as U.S. Pat. No. 10,517,715, each of which ishereby incorporated by reference in its entirety.

FIELD

This application relates generally to surgical procedures and, moreparticularly, to soft tissue reconstruction surgery.

BACKGROUND

A surgeon often has a variety of graft choices for replacing soft tissuein surgical reconstruction procedures. Two possible options includeautografts, tissues donated from the patient's own body, and allografts,tissue harvested from a donor, often a cadaver. Autografts can bebeneficial because the graft is harvested directly from the host and isaged correctly for the host. However, the added procedure required toharvest the graft from the patient can result in additional pain and anextended post surgical recovery period. In contrast, allografts canprovide added benefit over autografts because they do not require thepatient to recover from a bone and/or soft tissue harvesting operation.This can result in a faster healing time and a reduced amount ofphysical therapy following the procedure.

Allografts, unlike organ transplants, do not usually pose a risk forrejection by the host and, after being harvested from a cadaver, theycan be cleaned and frozen in liquid nitrogen for later use. Further, acadaver can be screened for any illness which can be transferred to thehost prior to harvesting any tissue or bone. However, the quality of anallograft is not always guaranteed. In the case of bone, for example,the quality of a graft can be dependent on the age and density of thebone being harvested. Additionally, chemical sterilization, irradiation,and other processing can compromise the quality of the bone.

Anterior Cruciate Ligament (ACL) repair is one example of a procedurewhere allografts are commonly utilized. Typically, a surgeon can replacea damaged ACL with a bone-tendon-bone (BTB) allograft taken from acadaver's patellar tendon or other tissue. As shown in FIG. 1 , theprocedure generally requires preparing a patient's knee for ACLreconstruction by forming two bone tunnels 6, 8, one in the tibia andone in the femur. The BTB allograft 1 can be drawn first through thetibial tunnel 6 and the femoral tunnel 8 such that one bone plug can besecured within the tibia and the other can be secured within the femur.The surgeon can draw the BTB allograft 1 through the tibial and femoraltunnels by pulling on a suture that is threaded through the tunnels anda bore formed in the leading bone plug.

If the quality of the leading bone plug is poor, however, the suture canpull through the bone plug during implantation. This is because thenarrow suture contacts the bone plug over a small area, and thereforeimparts significant pressure onto the bone plug when a surgeon or otheruser pulls the graft through the tunnels 6, 8.

Accordingly, there is a need for improved devices and methods forreinforcing tissue grafts. More particularly, there is a need forimproved bone plug reinforcement devices for use with tissue allografts.

SUMMARY

The devices and methods described herein generally provide improvedimplants that reinforce bone used in tissue grafts and can have a numberof advantages, including the ability to reinforce a bone plug of anyquality. Bone plug reinforcement inserts and implants including suchinserts can redistribute a load applied by a suture while a graft isbeing implanted within a patient because the suture can be pulledagainst the insert and the insert can, in turn, be pulled against theupper surface of a bone plug through-hole. The redistribution of theload is made possible by the increased contact area between the boneplug insert and the bone plug through-hole, thereby reducing thepressure applied to the bone plug at any one point. The lower pressurecan result in a lowered probability of bone plug failure. Additionally,in some embodiments the insert can be shaped such that it can beinserted into a bone plug through-hole in a manner that maintains adesired through-hole diameter and does not introduce new failure pointsby reducing the cross sectional area of the bone plug adjacent to thethrough-hole.

In one aspect, an implant can include a proximal end portion having athrough-hole formed therein, a distal end portion, and a reinforcinginsert disposed in the through-hole. The reinforcing insert can includea proximal face, a distal face opposed to the proximal face, and a firstupper surface extending between the proximal and distal faces. The uppersurface can have a generally convex shape that abuts against at least aportion of a sidewall of the through-hole. The insert can furtherinclude a second lower surface extending between the proximal and distalfaces. The lower surface can be opposed to and disposed below the firstupper surface, and can have a generally concave shape. The second lowersurface and portions of the sidewall of the through-hole not abutted bythe first upper surface can form a reinforced through-hole of theimplant.

The devices and methods described herein can include any number ofvariations or additional features, all of which are considered to bewithin the scope of the present invention. For example, in someembodiments, a radius of curvature of the first upper surface of thereinforcing insert associated with the generally convex shape can beapproximately equal to a radius of curvature of the portion of thesidewall of the through-hole against which the first upper surfaceabuts. In other embodiments, a radius of curvature of the second lowersurface of the reinforcing insert associated with the generally concaveshape can be approximately equal to a radius of the through-hole.

In some embodiments, a distance between a midpoint of the convex surfaceand a midpoint of the concave surface can be in a range between about0.5 millimeters and about 3 millimeters. In one embodiment, the distancecan be about 1 millimeter. In some embodiments, at least one of theproximal and distal faces can have a cavity formed therein for receivingan insertion tool. In some embodiments, the cavity can have a height anda width that are each in a range between about 0.5 mm and about 1.0 mm.

In certain embodiments, the implant can further include a suturedisposed in the reinforced through-hole. The suture can be manipulatedby a surgeon or other user to pull the implant into position within abone tunnel, and the reinforcing insert can be positioned between thesidewall of the through-hole and the suture during such an operation.

In other embodiments, the implant can be a bone plug. Indeed, in someembodiments the bone plug can be a bone-tendon-bone graft. In such anembodiment, a first bone portion of the implant can be part of theproximal end portion of the implant, a second bone portion of theimplant can be part of the distal end portion of the implant, and atendon can extend between the first and second bone portions.

The reinforced through-hole in the proximal end portion of the implantcan have a variety of shapes and sizes. In some embodiments, forexample, a cross-section of the reinforced through-hole can have acircular shape. This can be true even if, in certain embodiments, thecross-section of the through-hole has a non-circular shape.

In another aspect, a reinforced bone plug can include a bone plug havinga substantially cylindrical shape and a through-hole extendingtransversely across a longitudinal axis of the bone plug. The reinforcedbone plug can also include an insert positioned within the through-holesuch that a convex surface of the insert abuts against at least aportion of a sidewall of the through-hole and an opposing concavesurface of the insert intersects at least a second portion of thesidewall of the through-hole to define a reinforced through-hole in thebone plug.

Similar to the implant described above, the reinforced bone plug caninclude any number of variations or additional features, all of whichare considered to be within the scope of the present invention. In someembodiments, for example, a cross-section of the through-hole can beoblong and a cross-section of the reinforced through-hole can besubstantially circular.

In still other embodiments, a radius of curvature of the convex surfacecan be substantially equal to a radius of curvature of the portion ofthe sidewall of the through-hole against which it abuts. In otherembodiments, a radius of curvature of the concave surface can besubstantially equal to a radius of curvature of the second portion ofthe sidewall of the through-hole.

In addition, in certain embodiments the reinforced bone plug can furtherinclude a suture disposed in the reinforced through-hole. As mentionedabove, the suture can be manipulated by a surgeon or other user to pullthe implant into position within a bone tunnel, and the insert can bepositioned between the sidewall of the through-hole and the sutureduring such an operation.

In another aspect, a method for soft tissue surgical reconstruction caninclude forming a through-hole in a proximal end portion of an implantand positioning an insert having a convex surface opposed to a concavesurface within the through-hole such that the convex surface abutsagainst at least a portion of a sidewall of the through-hole to form areinforced through-hole. The method can also include threading a suturethrough the reinforced through-hole, and drawing the implant into a bonetunnel by pulling on the suture threaded through the reinforcedthrough-hole.

In some embodiments, the through-hole can have an oblong shape. In otherembodiments, the suture can abut against the concave surface of theinsert when pulled to draw the implant into the bone tunnel. In stillother embodiments, the implant can include a bone plug having a tendoncoupled thereto, the through-hole can be formed in the bone plug, andthe portion of the sidewall of the through-hole against which the convexsurface abuts can be a proximal end portion of the sidewall disposed ata location that is opposite to the tendon coupled to the bone plug.

In another aspect, a method for reinforcing a bone plug can includepositioning an insert having a convex surface opposed to a concavesurface within a through-hole formed in a bone plug such that a convexsurface of the insert abuts against at least a portion of a sidewall ofthe through-hole and the concave surface of the insert and otherportions of the sidewall of the through-hole form a reinforcedthrough-hole for the bone plug.

In some embodiments, the method can also include expanding thethrough-hole to form an oblong through-hole prior to positioning theinsert within the through-hole formed in the bone plug. In certainembodiments, a width of the oblong through-hole can be approximately thesame as a diameter of the through-hole prior to being expanded. In stillother embodiments, the portion of the sidewall of the through-holeagainst which the convex surface abuts can be the most proximal portionof the sidewall, the portion of the sidewall being disposed at alocation that is opposed to an end of the bone plug being configured tohave a tendon associated therewith.

In another aspect, a bone plug reinforcing insert can include a proximalface, a distal face opposed to the proximal face, and a first uppersurface extending between the proximal face and the distal face andhaving a generally convex shape. The insert can also include a secondlower surface extending between the proximal face and the distal face,the second lower surface being opposed to and disposed below the firstupper surface, and the second lower surface having a generally concaveshape. Further, the insert can be configured to be positioned within abone plug through-hole such that the first upper surface abuts againstat least a portion of a sidewall of the through-hole.

The bone plug inserts described herein can be formed from a variety ofbiocompatible materials known in the art. The insert can be formed frommaterials having a strength or density greater than that of the boneplug itself, so as to ensure that a suture cannot pull through theinsert. In some embodiments, for example, the bone plug can be made froma polymer, a metal, or another biocompatible material. Suitablebiocompatible materials can include, for example, metals such asstainless steel and titanium. In certain embodiments, differentcomponents can be made from different materials, e.g., the insertiontools discussed below can be formed from a metal material, while thebone plug insert can be formed from a polymer.

As mentioned above, the bone plug reinforcing inserts described hereincan be shaped and sized to fit within a variety of different bone plugthrough-holes. For example, the bone plug through-hole can have asymmetric (e.g., circular, elliptical, etc.) shape, or an asymmetricshape.

In another aspect, a bone plug can include a graft having a proximal endand a distal end, the proximal end having a through-hole formed therein,and the through-hole having a bone plug reinforcing insert as describedabove disposed therein such that the first upper surface of the insertabuts against at least a first portion of a sidewall of the through-holeand the second lower surface of the insert and a second portion of thethrough-hole form a reinforced through-hole.

In another aspect, a reinforced bone plug includes a bone plug having asubstantially cylindrical shape and a through-hole extendingtransversely across a longitudinal axis of the bone plug. The reinforcedbone plug also includes an insert positioned within the through-holesuch that a convex surface of the insert abuts against at least aportion of a sidewall of the through-hole and an opposing concavesurface intersects at least a second portion of the sidewall of thethrough-hole to define a reinforced through-hole in the bone plug.

In some embodiments, a cross-section of the through-hole can be oblongand a cross-section of the reinforced through-hole can be substantiallycircular. In other embodiments, a radius of curvature of the convexsurface can be substantially equal to a radius of curvature of theportion of the sidewall of the through-hole against which it abuts. Instill other embodiments, a radius of curvature of the concave surfacecan be substantially equal to a radius of curvature of the secondportion of the sidewall of the through-hole. The radii of curvaturediscussed above can have any of a variety of values, but in someembodiments can be about 2 millimeters each.

BRIEF DESCRIPTION OF THE DRAWINGS

The aspects and embodiments of the invention described above will bemore fully understood from the following detailed description taken inconjunction with the accompanying drawings, in which:

FIG. 1 illustrates a patient's knee during a ligament repair procedure;

FIG. 2A illustrates one embodiment of an implant including a pullsuture;

FIG. 2B illustrates an alternative embodiment of an implant including apull suture;

FIG. 2C illustrates another embodiment of an implant including a pullsuture;

FIG. 3 is an isometric view of one embodiment of a reinforcing insert;

FIG. 4 is a side-view of one embodiment of an implant including thereinforcing insert of FIG. 3 ;

FIG. 5 is an isometric view of an alternative embodiment of areinforcing insert;

FIG. 6 is a side-view of one embodiment of an implant including thereinforcing insert of

FIG. 7A is a front isometric view of another alternative embodiment of areinforcing insert;

FIG. 7B is a rear isometric view of the reinforcing insert of FIG. 7A;

FIG. 8A is a side view of a first step for preparing an implant having areinforced bone plug through-hole;

FIG. 8B is a side view of a second step for preparing an implant havinga reinforced bone plug through-hole;

FIG. 8C is a side view of the implant of FIGS. 8A-8B including thereinforcing insert of FIG. 7 ; and

FIG. 9 is an isometric view of one embodiment of a tool that can be usedto form the oblong through-hole of FIG. 8B.

DETAILED DESCRIPTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the devices and methodsdisclosed herein. One or more examples of these embodiments areillustrated in the accompanying drawings. Those skilled in the art willunderstand that the devices and methods specifically described hereinand illustrated in the accompanying drawings are non-limiting exemplaryembodiments and that the scope of the present invention is definedsolely by the claims. The features illustrated or described inconnection with one exemplary embodiment may be combined with thefeatures of other embodiments. Such modifications and variations areintended to be included within the scope of the present invention.

Additionally, to the extent that linear or circular dimensions are usedin the description of the disclosed devices and methods, such dimensionsare not intended to limit the types of shapes that can be used inconjunction with such devices and methods. A person skilled in the artwill recognize that an equivalent to such linear and circular dimensionscan easily be determined for any geometric shape. Further, in thepresent disclosure, like-numbered components of the embodimentsgenerally have similar features. Still further, sizes and shapes of thedevices, and the components thereof, can depend at least on the anatomyof the subject in which the devices will be used, the size and shape ofcomponents with which the devices will be used (e.g., the allograft orautograft), and the methods and procedures in which the devices will beused.

Described herein are devices and methods for reinforcing a tissue graftor other implant that can provide a number of advantages, including theability to reinforce a bone plug of any quality. For example, areinforcing insert according to the teachings of the present inventioncan be used preventatively when the quality of a bone plug is inquestion or known to be inferior. In such an instance, an insert can beinstalled in a through-hole of the bone plug to distribute forces from asurgeon pulling on a suture extending through the through-hole whenpositioning a graft or other implant. The insert can better distributethese loads because it contacts the sidewalls of the bone plugthrough-hole over a greater area than the suture alone. Any installationforces can be distributed over the larger area and the pressure appliedto the bone plug at any one point can be decreased. The lower pressurecan decrease the likelihood of the bone plug failing due to suturepull-through. Moreover, in some embodiments the insert can be shapedsuch that it can be inserted into a bone plug through-hole in a mannerthat maintains a desired through-hole diameter and does not introducenew failure points by reducing the cross sectional area of the bone plugadjacent to the through-hole.

Implantation of an ACL graft can generally require preparation of thepatient's knee, as shown in FIG. 1 . The surgeon can incise the patientat the knee to expose the knee joint. After the knee joint has beenexposed, the surgeon can remove the damaged soft tissue and createtibial and femoral bone tunnels 6, 8, which can receive the bone plugportions of an implant 1, such as a BTB graft. Once the knee is properlyprepared for the implant, the surgeon can thread a suture 4 through athrough-hole 3 in a leading bone plug 2, as shown in FIGS. 2A-C. If theimplant 1 is supplied without a through-hole in the leading bone plug 2,a surgeon can drill, punch, or otherwise form an appropriately sizedthrough-hole in the bone plug 2 for this purpose. Any number of sutureconfigurations can be used to secure the suture 4 to the bone plug 2.For example, FIG. 2A shows a straight pull configuration of the suture 4where the suture is threaded through the bone plug through-hole 3 andthe two free ends can be manipulated by a surgeon. FIGS. 2B and 2C showalternative embodiments where the suture 4 includes a cortical button 5around which the suture is looped and knotted so as to create one ormore suture loops 7, 7′ extending from the button 5, as well as a freeend of the suture 4 that can be used to pull the implant 1 intoposition. The suture loops 7, 7′ extending below the cortical button 5and through the through-hole 3 can have an adjustable length (as shownin FIG. 2B, loops 7) or a fixed length (as shown in FIG. 2C, loops 7′),depending on how the suture is threaded through and knotted about thecortical button. Exemplary cortical buttons and suture threadingconfigurations are disclosed in U.S. Pat. No. 9,757,113, entitled“Adjustable Graft Fixation Device,” as well as U.S. Pat. No. 9,974,643,entitled “Implant Having Adjustable Filament Coils,” and U.S. Pat. No.10,405,968, entitled “Implant Having Filament Limbs of an AdjustableLoop Disposed in a Shuttle Suture.” The disclosures of each of theseapplications are hereby incorporated by reference in their entirety asif their entire contents were reproduced herein.

As shown in FIG. 1 , the implant 1 can be positioned within a patient'sbody by guiding the suture 4 through the tibial tunnel 6 and the femoraltunnel 8. Once the suture 4 has been threaded through the bone tunnels,the surgeon can use the suture 4 to pull the implant 1 into place (e.g.,to a position in which the bone plug 2 rests in the femoral bone tunnel8, the bone plug 12 rests in the tibial bone tunnel 6, and the implant 1extends between the femur and tibia). When the surgeon has properlyimplanted the BTB graft or other implant 1 in the patient's knee, thebone plug ends of the graft can be secured within the tunnels such thatthey are fixed relative to the tibia and femur (e.g., using cross pins 9or other fixation elements). While reference is made herein to a BTBgraft commonly utilized in ACL reconstruction, the bone plug insert canbe readily used in reconstruction of other soft tissue as well.

A BTB allograft for an ACL reconstruction procedure can be harvestedfrom a cadaver by a technician prior to the reconstruction procedure.The cadaver can be screened for any potential diseases to avoidinfecting the patient undergoing the reconstruction procedure. While acadaver can be screened for disease, the quality of the BTB allograftcan still vary significantly based upon the age and/or health of thecadaver. As a result, the quality of the bone plugs of the BTB allograftmay not be known. A technician can harvest a BTB graft by cutting aportion of the patellar tendon 10 that includes bone plugs 2, 12 fromthe tibia and patella at either end. Other known allograft tissue caninclude the Achilles, tibialis and peroneus longus tendons, as well asthe anterior cruciate ligament itself. The bone plugs 2, 12 can have agenerally cylindrical shape extending along a longitudinal axis L andcan have at least one through-hole formed therein that extends throughthe bone plug in a direction perpendicular to the longitudinal axis.Just as the bone plugs provided for herein can be used in otherprocedures, other configurations of grafts can also be used inconjunction with the disclosures provided for herein without departingfrom the spirit of the present disclosure. The disclosures pertaining tothe size and shape of grafts and plugs in no way limit the applicabilityof the present teachings. In particular, the disclosures pertaining to abone plug reinforcing insert can be applied to any number of grafts,plugs, or other related types of implants.

After a graft has been harvested, a technician can process the graft forpackaging and use. Processing of the graft can include cleaning thegraft and freezing it in liquid nitrogen for preservation andsterilization. Other processing and sterilization techniques can beused, including treating the graft with low dose irradiation and/orchemical disinfectants or any other processing and sterilizationtechniques known in the art.

As discussed above, the surgical procedure for ACL reconstruction caninclude drawing an implant 1 into a bone tunnel by pulling on a suturecoupled to the implant. For example, the bone plug 2 can be drawnthrough the tibial and femoral bone tunnels 6, 8 by pulling on thesuture 4, as shown in FIGS. 2A-2C. If the bone plug 2 is of poor initialquality, or has been degraded by irradiation or other sterilizationtechniques performed during processing, the leading suture 4 (FIG. 2A)or loops 7, 7′ (FIGS. 2B, 2C, respectively) can pull straight throughthe bone plug 2 during implantation. The risk of the suture pullingthrough the bone plug can be present even with high quality bone graftsdue to the concentrated forces applied to the bone plug by the suture.That is, the pulling force applied to the suture is typicallytransmitted to the bone plug over a small contact area, thereby creatinga large amount of pressure at the point of contact.

One solution to this problem can be to distribute the loading forcesapplied to the bone plug over a larger contact area, thereby reducingthe pressure on the bone plug. FIG. 3 illustrates one embodiment of abone plug reinforcing insert 120 for this purpose. The bone plug insert120 can have a generally cylindrical shape and can include athrough-hole 122 extending therethrough. The cylindrical bone pluginsert 120 can be positioned within a through-hole 140 of a bone plug102, as shown in FIG. 4 . The cylindrical bone plug insert 120 can besized so that it can be inserted within the bone plug through-hole 140with no additional preparation to the bone plug. Sizing the cylindricalbone plug insert 120 to have an outer diameter D₁ about equal to thediameter D₂ of the through-hole 140 of the bone plug 102 can maximizethe amount of material present in the bone plug 102 and thereby maintainthe structural integrity of the bone plug 102.

In some embodiments it can be desirable to maintain at least a minimumvalue for a diameter D₃ of the bone plug insert through-hole 122. Forexample, it may be desirable for the diameter D₃ to be at least equal toa diameter of the through-hole 140 that would be formed in the bone plugin a case where no insert 120 is used. This diameter can be determined,for example, by a minimum diameter necessary to pass one or more sutureloops through the bone plug through-hole 140. In such instances, theinsert 120 can be constructed such that its inner diameter D₃ (i.e., thediameter of the bone plug insert through-hole 122) is equal to orgreater than the minimum value. Doing so necessarily increases the outerdiameter D₁ of the insert 122, however, and requires that the diameterof the bone plug through-hole 140 be larger than it might otherwise haveto be if no insert were used. Forming a larger diameter bone plugthrough-hole 140 removes additional material from the bone plug 102,which in turn can weaken the bone plug and increase the likelihood offailure in the area surrounding the through-hole 140 due to thedecreased amount of material. This can be especially true in theoften-narrower width direction extending perpendicular to a longitudinalaxis L of the bone plug 102 (e.g., the portions 103 extending betweenthe sidewalls 102 s of the plug 102 and the outer edge of thethrough-hole 140, as shown in FIG. 4 ). However, the use of an insert120 can remain advantageous even despite the weakening that can occurwhen a larger bone plug through-hole 140 is formed to accommodate theouter diameter D₁ of the insert 120.

The bone plug insert 120 can be inserted into the bone plug 102 in avariety of different manners, depending at least in part on thematerials being used, the type of procedure being performed, and userpreference. By way of non-limiting example, the bone plug insert 120 canbe installed into the bone plug through-hole 140 prophylactically, forinstance if the bone plug is known to be of lesser quality that mightnot withstand installation forces. In some embodiments, the insert 120can even be installed after a suture 4 has torn through the bone plug102. In such an embodiment, use of a bone plug reinforcing insert 120can allow a graft to be used when it would otherwise normally bediscarded. A number of other methods known to those skilled in the artfor inserting a material into a bone plug can also be used.

The timing of when the bone plug insert 120 is inserted into the boneplug 102 can also vary. In some embodiments, once the cylindrical boneplug insert 120 has been installed within the bone plug 102, a surgeoncan thread the suture 4 through the reinforced hole and continue withthe implantation procedure. Alternatively, a suture 4 can first bethreaded through the cylindrical bone plug insert 120 and the bone plug102, and then the cylindrical bone plug insert 120, can be inserted intothe bone plug 102.

In some embodiments a suture may be disposed in a bone plug before abone plug insert is introduced. This can include embodiments such asthose illustrated in FIGS. 2B and 2C in which the suture ends are tiedand thus may not be easily accessible to thread the suture through thebone plug after a bone plug insert is introduced. A bone plug insertthat is configured to allow an internal surface of the insert to beaccessed directly from the through-hole of the bone plug can be utilizedin such instances. One exemplary embodiment of such a bone plug insertis the bone plug insert 220 illustrated in FIG. 5 .

As shown in FIG. 5 , the bone plug reinforcement insert 220 can have acylindrical shape with a slit 230 creating a “C” shaped cross section.The slit 230 can allow the insert 220 to be passed over a suture 4 andsubsequently positioned in a bone plug though-hole 240 without the needto remove the suture 4 or untie any knots. The insert 220 canalternatively be inserted into a bone plug 202 prior to threading asuture though the insert. After passing the insert 220 over a suture andpositioning it within a bone plug through-hole 240, the insert can berotated such that the slit faces away from the direction of loading(e.g., the upward direction, or the direction that the suture 4 isextending, in FIG. 6 ). This can prevent the suture 4 from slippingthrough the slit during implantation and coming into contact with thebone plug 202.

As mentioned above, when utilizing the bone plug inserts 120 and 220,surgeons may decide to increase the diameter of the through-hole 140,240 formed in the bone plug 102, 202 so that an inner through-hole 250of the insert can have a desired diameter D₃, such as approximately thesame diameter of a through-hole that would be formed in the bone plug202 if no insert were being used. Alternatively, surgeons may opt toleave the diameter of the through-hole 140, 240 formed in the bone plug102, 202 the same size as would be used without an insert, and thus usean insert with an inner through-hole 250 that has a smaller diameter D₃than would normally be formed in the bone plug 202 if no insert wereused.

In instances in which surgeons desire a particular diameter for thethrough-hole remaining after positioning of any insert (e.g., aparticular desired diameter for the inner through-hole 250 of the insert220), the surgeon will typically increase the diameter of thethrough-hole of the bone plug (e.g., the diameter D₂ of through-hole240). However, it can be detrimental to remove additional material froma bone plug in this manner because doing so can reduce thecross-sectional area of bone surrounding the through-hole, therebyintroducing additional failure points and increasing the likelihood ofbone plug failure. Moreover, it can be particularly detrimental toremove additional material in areas where the bone plug is already atits thinnest, such as in a width direction W extending perpendicular tothe longitudinal axis L of the bone plug. The bone plug is typicallythinner in this direction than it is along the longitudinal axis L dueto its generally cylindrical and elongate shape. As a result, in someinstances it can be desirable to maintain (i.e., not increase) adiameter of a bone plug through-hole in a width direction that extendsperpendicular to a longitudinal axis of the bone plug so as to maximizethe amount of bone material surrounding the through-hole. It can bedifficult to reconcile the competing goals of providing a bone plugreinforcing insert that does not restrict the diameter of the finalthrough-hole that receives sutures but also does not remove additionalmaterial from the bone plug at its weakest points (i.e., where thematerial thickness is already less than at other locations of the boneplug).

FIGS. 7A and 7B illustrate one embodiment of a bone plug insert 320 thatcan address the competing goals mentioned above and maintain both adesired diameter of a final bone plug through-hole and an amount of bonesurrounding the bone plug through-hole. The bone plug insert 320 ofFIGS. 7A and 7B can therefore provide surgeons with the benefits ofdecreased loading stresses on the upper portion of the bone plugthrough-hole 340 of the bone plug 302 (as shown in FIGS. 8A-8C),maintaining an initial diameter of the bone plug through-hole 340, andmaintaining the amount of bone plug material in the width direction W.In the illustrated embodiment, this is accomplished by enlarging thebone plug through-hole 340 in a length direction (i.e., parallel to alongitudinal axis L of the cylindrical bone plug 302) to accommodate theinsert 320 while not removing additional bone in the width direction W(i.e., perpendicular to the longitudinal axis of the cylindrical boneplug 302) of the through-hole 340, thereby creating an oblong-shapedthrough-hole (i.e., a through-hole having an oblong cross-section) intowhich the insert 320 can be inserted.

The bone plug insert 320 of FIGS. 7A and 7B can have a proximal face326, a distal face 328, a convex upper surface 322, and a concave lowersurface 324. The convex upper surface 322 and the concave lower surface324 can extend between the proximal face 326 and the distal face 328.The convex upper surface 322 and the concave lower surface 324 can becoupled to one another via connecting surfaces 332 that can extendbetween the proximal and distal faces 326, 328 of the insert. In someembodiments, the connecting surfaces 332 can be formed by chamfering anedge created by the intersection of the convex upper surface 322 and theconcave lower surface 324. In addition, in certain embodiments theinsert 320 can include first and second sidewalls 336, 338 extendingbetween the proximal and distal faces 326, 328, and also serving toconnect the convex upper surface 322 to the concave lower surface 324.The sidewalls 336, 338 can have a different radius of curvature than theconvex upper portion 322 or the concave lower portion 324, or can have aflat (i.e., planar) profile. In embodiments where a distance 334 betweenthe convex upper surface 322 and the concave lower surface 324 is large,first and second sidewalls 336, 338 can connect the upper and lowersurfaces without increasing the overall width 339 of the insert 320(i.e., maintaining the width 339 at or below the diameter oi). In someinstances, the convex upper surface 322 and the concave lower surface324 can encompass the sidewalls 336, 338. Further, in some embodimentsthe convex upper surface 322 and the concave lower surface 324 cancontact each other directly such that the connecting surfaces 332 arethe location at which the convex upper surface 322 meets the concavelower surface 324 without a formed chamfered edge or the like.

The bone plug insert 320 can increase the amount of pulling force that abone plug can successfully bear. After installation in a through-hole ofa bone plug (e.g., as shown in FIG. 8C), a suture disposed in thethrough-hole can contact the bone plug insert 320 on the concave lowersurface 324, which in turn can redistribute a pulling force across alarger surface area of the bone plug 302 via the concave upper surface322 that abuts against an upper surface of the bone plug through-hole340′.

The bone plug insert 320 can also include one or more features formedthereon that are configured to allow coupling of the bone plug insert320 to an insertion tool, or to facilitate grasping of the insert 320 bya surgeon or other user. For example, the proximal and/or distal faces326, 328 can include any number of surface features formed thereon, suchas one or more tabs or protrusions, one or more indentations, etc. thatcan facilitate grasping of the insert by hand and/or with one or moretools. These features, if they protrude from the surfaces 326, 328, canbe configured to snap off or otherwise be removed after the insert 320has been positioned within a bone plug through-hole. In otherembodiments, for example, the proximal and/or distal face 326, 328 ofthe bone plug insert can include a cavity 330, such as a drafted pocket,that can be used to accept a portion of an insertion tool used toposition the insert 320 within a bone plug through-hole. The cavity canhave any of a variety of shapes and sizes but, in some embodiments, thecavity can have a rectangular shape with a height and a width that arebetween about 0.5 millimeters and about 1.0 millimeter. The depth of thecavity can vary as well, and can be as shallow as 0.5 millimeters or canbe formed as a through-hole extending between the proximal and distalfaces 326, 328.

The bone plug 302, as shown in FIGS. 8A-8C, can receive the bone pluginsert 320 in a modified oblong through-hole 340′. As noted above, thebone plug 302 can have a circular or substantially circular though-hole340 created by a technician during an initial processing of the graft,or the through-hole 340 can alternatively be created by a surgeon at thetime of the implantation procedure. The through-hole 340′ can be made bymodifying the substantially circular through-hole 340 of the bone plug302 such that it has a non-circular or substantially non-circular shape,such as an oblong or elliptical shape opening (i.e., a cross-section ofthe opening is oblong in shape). In the embodiment shown in FIG. 8C, forexample, the modified through-hole 340′ can have a diameter ∅₁ at anupper end and a lower end thereof, with a constant width W₁ therebetween(the width W₁ can be equal to the diameter ∅₁). By not increasing thediameter of the modified through-hole 340′ in the width direction W(i.e., the left-right direction in FIGS. 8B and 8C), the bone plug canmaintain the amount of material surrounding the modified through-hole340′ at its thinnest points and provide for removing excess materialonly from an upper or lower surface of the through-hole 340 where thethickness of the surrounding bone plug is typically greater. Modifyingthe through-hole 340 in this manner can permit the use of the insert 320without restricting the diameter of the reinforced through-hole thatreceives sutures or introducing additional failure points for the boneplug. While the modified through-hole 340′ is described above as havingidentical diameters at its upper and lower ends, in other embodimentsthe modified through-hole 340′ can have one diameter at its upper endand a different diameter at its lower end. In such embodiments, theconvex upper surface 322 and the lower concave surface 324 of the insert320 can be shaped such that their radii of curvature match the radii ofcurvature of the upper and lower portions of the modified through-hole340′, respectively.

The diameters or radii of curvature of the upper and lower portions ofthe bone plug through-hole 340′ can be any of a variety of sizes,depending, at least in part, on the size of the bone plugs, sutures tobe passed through the bone plugs, and the type of procedure beingperformed. In some embodiments, for example, the diameter ∅₁ of themodified through-hole 340′ can be in a range of about 1 millimeters toabout 3 millimeters. In certain embodiments, the diameter ∅₁ of themodified through-hole 340′ can be about 2 millimeters. The length of thethrough-hole can be dictated, at least in part, by the size of the boneplug employed and the type of procedure being performed, but in someembodiments can be in a range of about 1 millimeter to about 8millimeters.

The bone plug insert 320 can be sized such that it can be inserted intothe modified through-hole 340′ so that the convex upper surface 322mates with or abuts against the upper surface 342 of the modifiedthrough-hole. Further, in some embodiments like the one illustrated inFIG. 8C, once the insert 320 is installed, a circular reinforcedthrough-hole can remain that has approximately the same diameter ∅₁ asthe initial through-hole 340. This can be accomplished because the lowerportion 344 of the modified through-hole 340′ can have the same diameteror radius of curvature as the concave lower surface 324 of the bone pluginsert 320. Alternatively, the convex upper surface 322, the concavelower surface 324, and the upper and lower portions 342, 344 of themodified through-hole 340′ can have different radii of curvature. In anycase, the radii of curvature of the upper surface of the through-hole340′ and the upper convex surface 322 can match, as can the radii ofcurvature of the lower surface of the through-hole 340′ and the lowerconcave surface 324. Moreover, in some embodiments the bone plug insert320 can have a particular height, i.e., a particular distance 334extending between midpoints M₁ of the upper convex surface 322 and M₂ ofthe lower concave surface 324 as measured along the proximal and/ordistal faces 326, 328. In some embodiments, for example, this distancecan also be in a range between about 0.5 millimeter and about 1.5millimeters, and can be about 1 millimeter in certain embodiments.

As mentioned above, the radii of curvature of the upper convex surface322 and the lower concave surface 324 can match the radii of curvatureof the upper portion of the through-hole 340′ and the lower portion ofthe through-hole 340′, respectively. Accordingly, in certain embodimentsthe radii of curvature of the upper convex surface 322 and the lowerconcave surface 324 can be in a range of about 0.5 millimeters to about1.5 millimeters. In some embodiments, the radii of curvature of thesesurfaces can be about 1 millimeter. The insert 320 can have any of avariety of lengths. For example, in some embodiments the insert 320 canbe as long as the through-hole 340′, i.e., as wide as the bone plug 302in the width direction W. In other embodiments, however, the insert 320can have a length extending between the proximal and distal faces 326,328 that is shorter than a length of the through-hole 340′, such thatthe insert is recessed from an outer surface of the bone plug 302 oncepositioned within the through-hole 340′. In some exemplary embodiments,a length of the insert can be in the range of about 2 millimeters toabout 20 millimeters, and in one exemplary embodiment the length can beabout 10 millimeters.

The bone plug insert 320 can be formed from any of a variety ofbiocompatible materials known in the art. Exemplary materials suitablefor use in forming the insert 320 can include stainless steel, titanium,and other biocompatible metals. Non-metallic materials, such as variousbiocompatible polymers, including polyether ether ketone (PEEK), canalso be used. A selected material should be able to withstand the forcesexperienced during installation and use of a tissue graft, so thatsutures are incapable of pulling through the insert in the same mannerthat can be experienced when using only a bone plug.

As shown in FIG. 8C, in use, such as during positioning of an implant ina patient, a suture 4 can contact the concave lower surface 324 of theinsert 320. Upward forces in the direction of arrow P can be applied tothe suture 4 and transferred to the bone plug 302 through the insert320. The insert 320 can distribute the forces over the surface area ofthe insert 320, and consequently can transfer the forces to the boneplug 302 over the surface area of contact between the upper convexsurface 322 and the upper portion 342 of the through-hole. Thisdistribution over a larger surface area can lower the pressure appliedto the bone plug 302 and the stress present in the bone plug 302 at anyone location. The better distribution of force can allow a surgeon topull the bone plug 302 through the femoral and tibial tunnels 6, 8 toproperly position the implant 1 with a decreased risk of bone plug 302failure.

In order to prepare the bone plug 302 for the bone plug insert 320, thesymmetrical (e.g., circular) through-hole 340 can be expanded into theoblong shape of the through-hole 340′ in a variety of manners. In someembodiments, the through-hole 340 can be modified using a punch 350, asshown in FIG. 9 , or another similarly-purposed tool or instrument. Thepunch 350 can be an elongate cylindrical tool with a longitudinal axisL′ extending between a proximal end 350 p and a distal end 350 d. Thepunch can include a protrusion 352 extending perpendicular to thelongitudinal axis L′ from an outer surface thereof. The protrusion 352can extend along the majority of a length of the tool 350 or, as shownin FIG. 9 , can extend along a relatively short distance. The punch 350can be manufactured out of any suitable material capable of forming boneand can be packaged with the insert or separate therefrom. Exemplarymaterials can include metals, such as stainless steel or titanium, aswell as suitable rigid polymers, such as PEEK.

Initially, the bone plug 302 can be prepared for installation byfollowing the steps illustrated in FIGS. 8A-C. The bone plug 302, asshown in FIG. 8A for example, can have a through-hole 340 which can beused to receive a suture 4 (shown in FIG. 8C), having a diameter of inthe range of about 1 millimeter to about 3 millimeters. Referring toFIG. 8B, the punch 350 can be inserted within the through-hole 340 andadvanced to create the modified through-hole 340′ for the insert 320. Asnoted above, the diameter of the tool 350 in the width direction W′, andsubsequently the diameter of the through-hole 340′ in the widthdirection W, can be maintained during this procedure. A proximal portionof the tool 350, which can have the same or a slightly smaller diameterthan the through-hole 340, can be inserted into the bone plugthrough-hole 340.

A surgeon or technician can push the punch 350 through the bone plugthrough-hole 340 such that the protrusion 352 forms the oblong shape ofthe modified bone plug through-hole 340′. Advancing the punch 350through the bone plug through-hole 340 can be done by hand or using atool, such as by using a mallet or a hammer. The punch 350 can beadvanced through the through-hole 340 so that the radially extendingprotrusion 352 removes additional material to create the oblong-shapedmodified through-hole 340′. The punch 350 can be advanced through thebone plug linearly without rotation so that the desired geometry of themodified through-hole 340′ is attained. A person skilled in the art willrecognize a variety of other geometries that can be formed in view ofthe disclosures herein, either using the punch 350, a punch having adifferent configuration, or using other techniques for forming and/ormodifying through-holes. In some embodiments, this procedure can becompleted just after the bone plug is harvested from a cadaver or, inother embodiments, can be performed by a surgeon during an implantationprocedure. In still other embodiments, the modified through-hole 340′can be created using other known methods, for example using a drillpassed through the bone plug at offset locations.

Once the modified through-hole 340′ has been formed, as shown in FIG.8B, a surgeon can install the bone plug insert 320. The bone plug insert320 can be placed in the modified through hole in a variety of manners,including by hand or with a tool. In embodiments that employ aninsertion tool, the insert 320 can be coupled to the tool via, forexample, a cavity 330 formed in the bone plug insert 320. One or moresuture loops or lengths of suture can be threaded through thethrough-hole 340′ either before or after insertion of the insert 320within the through-hole. The insert 320 can be positioned such that theone or more suture loops contact the insert, rather than the bone plug,when a surgeon applies a pulling force to the suture (e.g., such as aforce on the suture 4 in the direction P shown in FIG. 8C).

As mentioned above, the bone plug reinforcing inserts and associatedtools described herein can be formed from any of a variety ofbiocompatible materials. Suitable biocompatible materials can include,for example, metals such as stainless steel and titanium. Othermaterials, such as polymers, can also be used, provided the material canwithstand the forces that are experienced during installation and use.Further, in certain embodiments particular components can be made fromdifferent materials. For example, a medical driver tool can be made fromone material while an insert or other component can be made from adifferent material.

While the bone plug reinforcing inserts are typically left implantedwithin a patient, it is contemplated that the insert and other tools andassociated devices described herein can be designed for multiple usesand can be reconditioned for reuse after at least one use.Reconditioning can include any combination of the steps of disassemblyof the device, followed by cleaning or replacement of particular pieces,and subsequent reassembly. In particular, the device can bedisassembled, and any number of the particular pieces or parts of thedevice can be selectively replaced or removed in any combination. Uponcleaning and/or replacement of particular parts, the device can bereassembled for subsequent use either at a reconditioning facility or bya surgical team immediately prior to a surgical procedure. Those skilledin the art will appreciate that reconditioning of a device can utilize avariety of techniques for disassembly, cleaning/replacement, andreassembly. Use of such techniques, and the resulting reconditioneddevice, are all within the scope of the present invention.

Preferably, the bone plug reinforcement inserts and the associatedaccessories described herein will be processed before surgery. First, anew or used insert or accessory can be obtained and, if necessary,cleaned. The insert or accessory can then be sterilized. In onesterilization technique, the insert or accessory can be placed in aclosed and sealed container, such as a plastic or TYVEK bag. Thecontainer and its contents can then be placed in a field of radiationthat can penetrate the container, such as gamma radiation, x-rays, orhigh-energy electrons. The radiation can kill bacteria on the instrumentand in the container. The sterilized insert or accessory can then bestored in the sterile container. The sealed container can keep theinsert or accessory sterile until it is opened in the medical facility.In other embodiments, sterilization can be performed using any number ofways known to those skilled in the art including beta or gammaradiation, ethylene oxide, steam, or a liquid bath (e.g., cold soak).

All papers and publications cited herein are hereby incorporated byreference in their entirety. One skilled in the art will appreciatefurther features and advantages of the invention based on theabove-described embodiments. Accordingly, the invention is not to belimited by what has been particularly shown and described, except asindicated by the appended claims.

What is claimed is:
 1. An implant, comprising: a proximal end portionhaving a through-hole formed therein; a distal end portion; and areinforcing insert disposed in the through-hole, the insert comprising:a proximal face; a distal face opposed to the proximal face; a firstupper surface extending between the proximal and distal faces, the uppersurface having a generally convex shape that abuts against at least aportion of a sidewall of the through-hole; and a second lower surfaceextending between the proximal and distal faces, the lower surface beingopposed to and disposed below the first upper surface, the lower surfacehaving a generally concave shape, and the second lower surface andportions of the sidewall of the through-hole not abutted by the firstupper surface forming a reinforced through-hole of the implant.
 2. Theimplant of claim 1, wherein a radius of curvature of the first uppersurface of the reinforcing insert associated with the generally convexshape is approximately equal to a radius of curvature of the portion ofthe sidewall of the through-hole against which the first upper surfaceabuts.
 3. The implant of claim 1, wherein a radius of curvature of thesecond lower surface of the reinforcing insert associated with thegenerally concave shape is approximately equal to a radius of thethrough-hole.
 4. The implant of claim 1, wherein the distance between amidpoint of the convex surface and a midpoint of the concave surface isabout 1 millimeter.
 5. The implant of claim 1, wherein at least one ofthe proximal and distal faces has a cavity formed therein for receivingan insertion tool.
 6. The implant of claim 1, further comprising asuture disposed in the reinforced through-hole.
 7. The implant of claim1, wherein the implant is a bone plug.
 8. The implant of claim 7,wherein the bone plug is a bone-tendon-bone graft, with a first boneportion of the implant being part of the proximal end portion of theimplant, a second bone portion of the implant being part of the distalend portion of the implant, and a tendon extends between the first andsecond bone portions.
 9. The implant of claim 1, wherein a cross-sectionof the reinforced through-hole has a circular shape.
 10. The implant ofclaim 1, wherein a cross-section of the through-hole has a non-circularshape.
 11. The implant of claim 10, wherein a cross-section of thereinforced through-hole has a circular shape.
 12. A reinforced boneplug, comprising: a bone plug having a substantially cylindrical shapeand a through-hole extending transversely across a longitudinal axis ofthe bone plug; and an insert positioned within the through-hole suchthat a convex surface of the insert abuts against at least a portion ofa sidewall of the through-hole and an opposing concave surface of theinsert intersects at least a second portion of the sidewall of thethrough-hole to define a reinforced through-hole in the bone plug. 13.The reinforced bone plug of claim 12, wherein a cross-section of thethrough-hole is oblong and a cross-section of the reinforcedthrough-hole is substantially circular.
 14. The reinforced bone plug ofclaim 12, wherein a radius of curvature of the convex surface issubstantially equal to a radius of curvature of the portion of thesidewall of the through-hole against which it abuts.
 15. The reinforcedbone plug of claim 12, wherein the radius of curvature of the concavesurface is substantially equal to a radius of curvature of the secondportion of the sidewall of the through-hole.
 16. The reinforced boneplug of claim 15, further comprising a suture disposed in the reinforcedthrough-hole.
 17. A method for soft tissue surgical reconstruction,comprising: forming a through-hole in a proximal end portion of animplant; positioning an insert having a convex surface opposed to aconcave surface within the through-hole such that the convex surfaceabuts against at least a portion of a sidewall of the through-hole toform a reinforced through-hole; threading a suture through thereinforced through-hole; and drawing the implant into a bone tunnel bypulling on the suture threaded through the reinforced through-hole. 18.The method of claim 17, wherein the through-hole has an oblong shape.19. The method of claim 17, wherein the suture abuts against the concavesurface of the insert when pulled to draw the implant into the bonetunnel.
 20. The method of claim 17, wherein the implant includes a boneplug having a tendon coupled thereto, the through-hole is formed in thebone plug, and the portion of the sidewall of the through-hole againstwhich the convex surface abuts is a proximal end portion of the sidewalldisposed at a location that is opposite to the tendon coupled to thebone plug.